Mattg4321

If I had any idea how to get hold of or use an audio spectrum analyser…!! Are there any iPhone apps any good?

I’m 99% sure it’s noise from the unit though. If foam lining the manifold did absolutely nothing, then I doubt lining the plenum will?

An update to this. I tried lining the manifold with acoustic eggbox foam, on all sides. It made absolutely zero difference. I’ve noticed that running the unit at different speeds makes no difference. It just changes the pitch of the droning noise slightly. The unit is only set at 20% anyway as that’s all that’s needed to meet the airflow in the various guidelines. Turning it down to the minimum 15% the unit can operate out doesn’t improve matters. I’ve also noticed that the noise is significantly worse in bed 1 and the dining room/kitchen supply terminals. The only 2 rooms where there is currently a double run of 75mm ducting from the manifold (and roughly double the airflow). These are also the 2 longest runs! The other 3 bedrooms are just about acceptable, whereas bed 1 in particular definitely isn’t. I noticed that in certain areas of bed 1 and with your head turned a certain way, you can’t hear the noise. Unfortunately my pillow does not fall into that category! The terminal is located past the foot of the bed and to the side, so it seems to be a normal position for it. If I close the terminal completely in bed 1, it stops the noise, so it can’t be noise transmission through anything other than the ductwork from the unit itself imo. It’s not the terminal making the noise either because it still makes it even when it’s removed and the ceiling plenum visible. I’m going to have to look at fitting a proper silencer (not the useless semi flexible one I currently have). It’s doing to be pretty awkward, but I think doable if it’s 5-600mm in length. Diameter is not really restricted. Any suggestion on all the above? Which specific silencers at that length are best? I’ve looked at Lindab, but they only seem to do 160mm - slightly annoying as my ductwork is 150mm! Thanks.

Which flexible attenuator did you use on the ductwork to bedroom? How did you adapt it onto the semi rigid ducting? I have a double run to the bedroom

Thanks guys, I think that explains it. It was mainly through interest. Nothing is really wrong. I'm not planning to change the boiler as it's not very old. System is sealed with expansion vessel and pump in airing cupboard - so it effectively works as a system boiler, just the EV and pump are outside the boiler, which is actually preferable imo. I will be swapping out the existing controls for Vaillant and running PDHW when I get a spare minute

Leaving aside any comments re why I want to know/is this a good boiler at least initially... Can anyone explain why the figures for nominal heat output and modulation don't seem to tally up with eachother. Interested as much as anything and can't find any info.

Most people CGAF about CO2 in my opinion. Certainly not enough to commit to spending vast or even modest amounts of their money on. Far more important things to worry about than reducing a gas that is important to us, has no effect on human health and may or may not be causing some small amount of global warming.

Or use gapotape. Expensive though

I’ve actually got a Sunsynk. 5.5 I think it is. No complaints after a year. &nbsp I’ve wired it to run some circuits in island mode when power goes out too

Why not just get an inverter that will allow you to generate and use the full extent of your solar array, but only export the small amount that is allowed. Make sure you have enough battery storage to keep you going for at least 24 hours with no generation and don’t wildly oversize the array if you can’t export much as it’ll only be of any (limited) use in the winter/low sun days.

Tried that and it made no difference. I think vibration would be dealt with by the flexi silencer anyway. I’m pretty sure the noise is from the unit and the silencer isn’t dealing with it effectively. The fact I have spiral ducting and a metal box as a manifold aren’t helping either, when some others have silencing material in their manifolds/foam ducting. I just need to find time to take it apart now

Thanks all. It seems I’m not the first to come to the conclusion the BPC flexi silencers are not good, so it’s either replace that - probably with something homemade due to the awkward position of it. Or, line the manifold with acoustic foam to see if that can work as a second silencer. Which is probably the easier option, so the one I’ll try first.

Do that with that Type AC RCD and he won’t be fitting an EV charger to it though. You need Type A or ‘better’ RCD protection to fit an EV charger. It also needs to be double pole/switched neutral, which rules out the kind offer of the C40 RCBO above, which is only single pole, albeit Type A. Nothing necessarily wrong with that board. Swap out the RCD for a Type A and fit some Type A RCBO’s in place of the unprotected MCB’s and it’ll be fine. If you go to that extent though, you’re most of the way to a new board. If I was asked to fit an EV charger there on a budget I’d be fitting a 100A Type A RCD in place of the existing and an MCB for the charger. I can’t recall off the top of my head if the Wylex switched neutral RCBO’s fit that particular board - they keep changing them and they’re not always backwards compatible, it’s a bloody pain.

What silencer do you have @JohnMo?

Thanks, I’ll definitely give that a go. My gut feeling is that it’s fan noise/noise from the unit being transmitted through the ducting though. I don’t think the ducting even touches the plasterboard as it passes through. It’s then just foamed in.

MVHR mounted to ply on stud wall and solid ducting up into the loft via a 90 fitting. Then there’s the flexi silencer and only then is the manifold a few joists away, so it’s almost certainly not going to be vibration I’d say. I think it’s fan noise. Possibly being amplified by the manifold/ducting? I’m no expert on acoustics though. I think we’re on the same page re droning noise. The old bathroom extractors were way noisier from an air noise point of view. But any drone wasn’t really noticeable. These were in line units fitted in loft.

To add to this, just been weighing up my options, other than accepting that’s as good as it gets with this unit… 1. Change silencer for something else. Will be awkward because of space, which is a big part of the reason I went flexi to start with. 2. Fit those foam disc baffles where you poke sections out. Problem with this is where? Fitting in the terminal doesn’t seem like it would help much to me - only a gut feeling. 3. Do something with the manifold box, which seems like it could be part of the reason for the noise, or at least an option for a solution. A square box with flat hard sides might be amplifying any sound. I could pull this out without too much trouble and use the 150mm entry hole for access to line the sides with eggbox acoustic foam? I wonder how much difference this would make as the 150mm inlet from the MVHR is still directly in line with the outputs. I’m not an expert, but guess the sound ‘bounces around’ rather than travelling in a straight line, past the eggbox foam?!!

I’ve finally got my system up and running and slightly disappointed with the slight droning noise I’m getting from the supply terminals. It’s by no means horrendous, but quite a few people on here say they can’t hear it even with their ear to it. Perhaps I’m (and also my wife!) sensitive to it, or perhaps it’s the unit I’ve chosen/the silencer I’ve fitted. Would be grateful for your thoughts. I have the Vent Axia sentinel kinetic fh With this silencer between both the supply and extract manifolds https://bpcventilation.com/products/quiet-vent-semi-flexible-silencer-range?variant=53736188707142 These manifolds https://bpcventilation.com/products/quiet-vent-10point-re?variant=53736193753414&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gad_campaignid=22309731029&gbraid=0AAAAADpzxaWZxxdpXsjssay4R_gcCEWm-&gclid=Cj0KCQjwrojHBhDdARIsAJdEJ_fCPWKRHSNb-UR7UjrVugdzT9dmzVPeRhvT1YwSjs0a52VTXHXolz8aAivpEALw_wcB A double run of 75mm semi rigid ducting to the bedroom. The terminal is just past the foot of the bed and to the side by about 300mm. Unit is set to 15% overnight and still audible. Although to be honest not a great deal of difference between 15% and 40% boost. The drone stays similar. The air noise becomes audible as you get above 30-35% Edit: To clarify the noise is from all supply terminals. The extract terminals don’t really suffer the problem, or it’s much reduced - which probably makes sense to me. Thanks

The ‘metal centre’ doesn’t pass all the way through the coiled part of the spring clip. Just squeeze the coiled part together using the screwdriver for leverage and pop the spring clip off the fitting. It’s quite easy when you know how, but I’ve done it quite a few times!

As above, take the springs off. Use a small screwdriver for leverage if necessary. Had to do this a few times myself for various reasons

Doesn’t make a huge difference to electrician if you’re doing it properly imo. 35mm boxes still need chopping in a bit for D&D. You don’t want 25mm boxes - that’s for new build estate s@&£boxes. Same with capping. I always like to fit it even if D&D. Clipping only runs a higher risk of damage from other trades chucking materials around etc.

Our fitter insisted upon two stages of self levelling compound/feather edge on top of the liquid screed

I haven’t. I’ll give it a go though. There’s some great stuff around these days on the newer platforms though. Legacy media is dead imo - total tripe nearly all of it. The lack of understanding of how even a small business functions by those at the top of government is staggering. If they can’t even understand that then what chance do they have with the financial markets. Another set of tax rises in the autumn could be the thing that tips us into a pretty severe financial crisis. Labour have already found out that raising the rate of capital gains tax actually brought them less in tax receipts - will they learn?!

And it sounds like they’ll be coming back with more tax rises in the autumn. I’m genuinely worried for the future of this country. 4 more years of this lot and no prospect of anything much better to vote for. Someone who has actually run a business, rather than a career politician would be nice.